Monitoring and Modeling of Desertification Intensity Using Landsat Satellite Images (Case Study of Yazdanabad-Zarand watershed).

The phenomenon of desertification occurs in a wide range of climates from arid and semi-arid to semi-humid regions and is caused by natural factors and improper human performance. The Yazdanabad watershed is an active center of desertification in Kerman province, Iran and has been subject to human activities and climatic changes, especially drought.The present research aims to study the desertification potential of the Yazdanabad watershed in Zarand, Kerman province using remote sensing data for a 20-year period from 2000 to 2020.Land use maps were first developed for 2000 and 2020. Then, the relationship between the soil-adjusted vegetation index (SAVI) and the Albedo climatic index derived from TM and OLI Landsat images was used.Finally, using this relationship, the desertification divided index (DDI) was employed to derive different desertification classes.The results show that over 88% of the Yazdanabad watershed has been composed of bare land, which has shrunk over the studied periodwhereas saline land use, agricultural land use, and residential and man-made areas have expanded by about 94.39, 830.91, and 1106.30 ha, respectively.The mean annual trend of both SAVI and Albedo revealed the descending trend of the former and the ascending trend of the latter.The DDI-derived desertification classes in 2000 and 2020 show that over 88% of this plain is in the very severe and severe desertification classes. This means that the plain is extremely vulnerable to land changes and degradation given its climatic conditions and fragile vegetation cover.